As a senior Chemical Engineering student, I spend a lot time on my senior design project. Basically, each senior forms a group with one or two other students from the senior design class, and each group is assigned a project and an industry consultant. The industry consultant is supposed to guide you through the project and provide help when needed. There are weekly progress meetings with professors and oral presentations on certain weeks of the semester. Most of the groups use the simulation software, Aspen Plus, to model the process.
My group is assigned the Ethylene Oxide Production project. The goal of our project was to optimize the operation of the Ethylene Oxide production process in order to produce 50,000 metric ton per year to meet a contract with another company.
A little background about ethylene oxide: Ethylene oxide(EO) is colorless gas with chemical formula C2H4O. It is not to be confused with Acetylaldehyde, which also has the the formula C2H4O. EO has the unique epoxy structure that acetylaldehyde don’t have, and it is the simplest epoxide. It also has a pleasant aroma, but it is highly toxic and carcinogenic. EO can have violent self-polymerization with exposure to heat, acids, or bases. It’s commercially used mostly for ethylene glycol production. In addition, EO is extreme flammable and reactive, with a wide flammability limit of 3-100% in air. The NFPA fire Diamond for EO is shown below to demonstrate its dangerousness.
The reaction of the EO product is as follows
Primary reaction: Catalytic oxidation of Ethylene over Silver catalyst:
C2H4 + 0.5 O2 → C2H4O
Secondary reactions: Combustion, undesired:
C2H4 + 3 O2 → 2CO2 + 2H2O
Further Combustion of EO, undesired
C2H4O + 2.5 O2 → 2CO2 + 2H2O
The first reaction is the desired reaction, which involves the semi combustion of ethylene into ethylene oxide. The second and third reaction are the undesired side reactions, and we’re trying to limit these as much as possible. As a group, we’re supposed to study the reaction kinetics and input these in the Aspen software, so that the accurate reaction profile can be modeled.